We tend to believe that we have a natural instinct for the truth but the web has many inaccuracies that are commonly held to be factual. We can follow the old journalistic principle of getting at least two reliable sources for important pieces of information, but much of the internet is a mash up of other bits of the internet. The resulting multiplicity of sources might suggest a breadth of knowledge but in reality if a factoid is convincing enough it can spread.

Wikipedia is amongst the most reliable of sources because the content is genuinely the result of multiple entries, sometimes hundreds of them. Even Wikipedia has been guilty of significant errors – often the result of malicious editing. Prominent US journalist John Seigenthaler was incorrectly named as a suspect in the assassinations of both President John F Kennedy and his brother, Robert for example. The false information was the work of a man called Brian Chase, who said he was trying to trick a colleague at work.

A common error is that of the false obituary. It has even been know for false obituaries to be published on on separate occasions. Pre-written obituaries of entertainer Bob Hope were accidentally released on news web sites on two occasions and Pope John Paul II was the recipient of three separate reports of his demise. Other widely duplicated falsehoods on the internet include a report that Barack Obama is a muslim and that Bill Gates is giving away his fortune. This sort of widely distributed misconception is not the preserve of the Internet, for example the Great Wall of China Is not in fact nor ever has been, visible from the Moon, but the internet provides a distribution network that spreads these inaccuracies more widely and more quickly.

It is not just facts that are manipulated and distorted, the prevalence of powerful image manipulation tools means that photographs can not necessarily be trusted either. Even the celebrated news agency Reuters came under fire for this when in 2006 it published doctored images of an Israeli air strike in Beirut.